Fifth-wheel couplings provide the link between a trailer, such as a recreational vehicle, camper or a semi-trailer, and a towing vehicle, such as a pickup truck, a tow truck, a semi-tractor, or a leading trailer. The term “fifth wheel coupling” comes from a similar coupling used on four-wheel horse-drawn carriages and wagons that allowed the front axle assembly to pivot in the horizontal plane, to facilitate turning. The fifth wheel coupling comprises a kingpin that extends downward from a front end portion of the trailer, and a horseshoe-shaped hitch device or latch assembly, which is sometimes referred to as a fifth wheel on the rear of the towing vehicle. During towing, the kingpin rotates within the fixed fifth wheel as needed to allow the trailer to turn as the towing vehicle to which the latch assembly is attached turns. In particular, the kingpin rotates within the latch assembly as the trailer rotates behind the towing vehicle. Accordingly, the latching assembly captures and locks the kingpin in place in order to pull the towed vehicle. To reduce friction, grease is applied to the surface of the fifth wheel. In some cases, this fifth wheel arrangement is reversed with the kingpin attached to the towing vehicle and the latching assembly or hitch attached to the item to be towed.
For campers and other trailers, once the campers or trailers are uncoupled from the towing vehicle, the kingpin of the fifth wheel coupling is no longer needed for any functional use and extends downward from the camper or other trailer exposed and ready for the next time the camper or other trailer is to be attached to the latch assembly and towed by the towing vehicle. Thus, the only purpose for the fifth wheel kingpin on a camper or other trailer is to provide a linking mechanism for towing the respective camper or other trailer. For example, with a camper, the fifth wheel kingpin is not being used when the camper is at a camp site being occupied and used for camping purposes.
While not earlier recognized, the kingpin of the fifth wheel coupling that resides on a camper or trailer provides a mechanism that allows decorative and functional items to be secured to the camper or trailer.